Flexible exhaust pipe joint



Nov. 4, 1952 P. A. PlTT 2,616,728

FLEXIBLE EXHAUST PIPE J OIN'I' Filed Feb. 20, 1948 INVENTOR PAUL A. PITT BY 5 E a ATTORNEY Patented Nov. 4, 1952 V amer/2st; v FLEXIBLE EXHAUST rlris mm 7 Paul A. Pitt, San'Dieg'o, Calii'., assignor to Solar a Aircraft Company, San Diego, Calii'., a corporation of California Application February 2o, 194's', serialllo. 9,712 r 4Claims. (crass-11 i This invention relatesto flexible pipe joints and is particularly intended; for use in exhaust lines of aircraft" engines.

A general obj ectoi theinvention isto provide a practicable anddurable joint construction that especially in large sizes.

Other more specific objects and features of the inventionwill become apparent from the description to follow. 1

7 It "has heretofore been proposed to -form a is more'efiective 'insealing against gas leakage,

v flexible" joint in theexhaust line of an aircraft by providing a: pair oi 'spaced ap'art ball-type joints to permit the necessary flexing; and toprovide atelescqping joint between the ball-type joints to permit longitudinal extension and con- 7 traction. "It has also been proposed'to maintain contact between the nesting ball sections by the use of compression springs that act between'the two ball sections to urge them'apa'rt; V Inaccordance with the present invention, the seal between theball sections is maintained in part by gas pressure resulting from a novel construction including a bellows enclosing theptelescopic joint, and in part by a single, helical com-* pression .l rin i i e s in 3 on exerts a longitudinal force tending to maintain the ball sectionsin contact with each other, but reinforces. the bellows against radial expansion.

Referring now to the drawing, the single figure thereof is a side elevation, with a portion broken away, of a joint in accordance" with the invention. v The flexible joint constituting'the invention is shown in the drawing as" interconnecting two nipples I and I I, respectively, so that they can move either laterally or longitudinally relative to each other.

Thus the inner end Illa of the nipple ID is secured, as by welding, to a first sealing member consisting of a ball element I2 that extends outwardly about the nipple 10 and has an outer annular sealing surface I2a that seats against a complementary annular sealing surface on a second sealing member consisting of a sheet metal socket I3. The inner end of the socket I3 is attached, as by welding I4, to the outer end of an internal tube I5 which is in telescoping relation with an external tube I6. The internal tube 15 may have a Wear band I5a on its outer surface which bears against the external tube I6, and the latter may have an internal wear band IBa that bears against the internal tube I 5. The external tube I6 is secured at its outer end, as by welding I1, to the inner end of a socket I8 that is similar to the socket I2 and cooperates with a ball section I9 that is similar in all respects to the ball section I2 and is secured'by' welding 2 at its 'inner-end to the-'othernipple II. a

To prevent separation of :the ball element I2 and the socket'l3, a segment 20 may be provided exterior thereof, this segmentbeing of spherical curvature and being attached at its outer end by a collar 2| to the outer end of the ball element I2,

and having at its innerend a wearstripr 20a that bears against the'outer surface of the socket I3.

-Asimilar segment 22 and collar 23is'providedto retainthe socket I8againstrthe ball element I9. Inord'er 'to prevent leakage, the socket I3 must be urged against'the ball I2, and the socket I8 must beurged against the ballvl9. This is accomplished by-providing forces constantlyurging-the sockets I3 and IB" apart from each other and against their related ball surfaces.

' f To thisen'd; an outwardly extending-flange 25 ilar flange 26-issecured to the telescopingtube is secured to the telescoping tube I5, and a sim- I 6} and a tubular, corrugatedbellows 21- which surroundsrthe telescoping tubes I5, and I6, is

"secured at its'ends to the flanges 25 and 26,

respectively; Thusgthe bellows 2 1. is provided -withend mounting flangeszla and 2.112 which are bolted by bolts'l28 to lthe flangesi25zand 26, re-

spectively. To partially protect the bellows 21 from heat radiated from tubes I5 and.I6, a-.pair

of loosely' fittedtelescopic tubes- 29 =and-3ll are provided'interior of the bellows-21 but exterior helical configuration, which define a helical flange 21I and a helical groove 212. There is mounted within the helical groove 212 a compression spring 32, the major portion of which rests in the bottom of the helical groove 212 and is secured at its opposite ends against unwinding. Thus one end 32a is bent at right angles and connected by a hook 34 to the end mounting flange 21a of the bellows, while the other end 321) is similarly secured by a clip 35 to the end mounting flange 21b of the bellows.

The socket members I3 and I8 are urged apart against their associated ball members in part by the expansive force longitudinally of the spring 32, and in part by gas pressure developed within the annular chamber 40 between the telescoping tubes I5 and I6 and the bellows 21, which chambar is in communication with the exhaust gases being conducted by the joint through an aperture 42 in the telescoping member I5 and the flange 25.

In large sizes of joints, the pressure developed in the chamber 40 might seriously stress the bellows 21' radially and such stress is in part compensated for in accordance with the present invention by the spring 32 which, as previously indicated, is compressed longitudinally but is contracted radially. As the joint expands, the spring 32 tends to contract radially, and thereby further reinforce the bellows 21 against radial expansion when it is stretched.

Although for the purpose of explaining the invention, a particular embodiment thereof has been shown and described, obvious modifications will occur to a person skilled in the art, .and I do not desire to be limited to the exact details shown and described.

I claim:

1. A flexible joint for conveyance of fluid under pressure comprising: a first pair of spaced-apart sealing members having facing, annular sealing surfaces of spherical curvature and adapted to' be respectively connected to two conduits movable relative to each other;'a second pair of spacedapart sealing members having oppositelydirected annular sealing surfaces of spherical curvature seating against the annular sealing surfaces of said first sealing members; a tubular, longitudi- 11 nally expansible bellows member anchored at its opposite ends to and interconnectingsaid second pair of sealing members; said'bellows being normally compressed longitudinally whereby iturges said second pair of sealing members against the first'membersj'first and second pairs of telescoping tubular members positioned within said bellows member in spaced relation thereto, the

first pair being positioned within the second pair in spaced relation thereto, the two telescoping -members of each pair being connected respecto opposite endportions of said bellows'whereby radial expansion of said bellows nrestrained.

3. A flexible joint for fiuid'conduction under pressure comprising: a -first sealing member adapted to'be secured at-oneend to-a first 'conduit and having an annular sealing surface facing away from said first conduit; a second sealing member adapted to be connected to a second conduit and having an annular sealing surface seating against the sealing surface of said first member; a tubular longitudinally expansible bellows element interconnecting said second sealing member with said second conduit, said bellows element being compressed longitudinally and having a continuous helical corrugation and groove therein; and a helical compressionspring nesting in the bottom of said groove, the ends of'said spring being anchored to opposite end portions of said bellows whereby radial expansion'of said bellows is restrained and it applies an axial thrust from said second conduit to said second sealing member to urge it into sealing relation with said first sealing member.

:4. .A flexible joint for fluid conduction under pressure comprising: "a first sealing member adapted to be-secured at one end to a first conduit and having an annular sealing surface-of spherical curvature facing away from said first conduit; a second sealingmember adapted to be connected to a second conduit and having an annular sealing surface of spherical curvatureseating against the sealing surface of said first member; a tubular, longitudinally expansible bellows element interconnecting said second sealing member with REFERENCES CITED The following references are of record in the file of this patent:

'UNITED'STATES PATENTS Number .Name Date 289,265 Hurly Nov. 2'}, 1883 866,061 Phillips Sept.,l7, 1907 2,207,146 Fentress July 9, 1940 2,242,604 Wells May 20, 1941 2,414,987 Tobey Jan. 28, 1947 2,451,252 Stoeckly Oct '12, 1948 

